Add `read_wiki_page` function.

* gd_diff.py (read_wiki_page): New function.
* tests/test_gd_diff.py
(test_read_wiki_page_returns_none_if_wikipage_nonexistent)
(test_read_wiki_page_returns_content_if_wikipage_existent): Tests for
  `read_wiki_page`.

2 files changed, 30 insertions, 0 deletions

diff --git a/gd_diff.py b/gd_diff.py
index 84e1b60..5056cfc 100644
--- a/gd_diff.py
+++ b/gd_diff.py
@@ -405,6 +405,17 @@ def generate_wiki_page(release):
     return pkgs_noreadmes, wiki_page
 
 
+def read_wiki_page(release):
+    """Read wiki page for `release` from disk.
+    """
+    wp_file = wiki_page_path(release)
+
+    if not path.isfile(wp_file):
+        return None
+
+    return read_file(wp_file)
+
+
 def write_wiki_page(release, content):
     """Write wiki page `content` to `release`' last.rev file.
 
diff --git a/tests/test_gd_diff.py b/tests/test_gd_diff.py
index b4c0b6b..1dd0b5f 100644
--- a/tests/test_gd_diff.py
+++ b/tests/test_gd_diff.py
@@ -477,6 +477,25 @@ class TestGdDiff(object):
             assert wiki_page == gns_wiki_header() + '\n' + wiki_table
 
 
+    def test_read_wiki_page_returns_none_if_wikipage_nonexistent(self):
+        with mock.patch('os.getenv', new=self.env_func):
+            wiki_page_content = read_wiki_page('bogus-release')
+            assert wiki_page_content == None
+
+
+    def test_read_wiki_page_returns_content_if_wikipage_existent(self):
+        with mock.patch('os.getenv', new=self.env_func):
+            wp_file = wiki_page_path('bogus-release')
+
+            # write some bogus content
+            bogus_content = 'bogus content'
+            with open(wp_file, 'w') as f:
+                f.write(bogus_content)
+
+            wiki_page_content = read_wiki_page('bogus-release')
+            assert wiki_page_content == bogus_content
+
+
     def test_push_wiki_page(self):
         url = 'http://localhost:8080'
         user = 's'